Assertion (A): Insectivorous plants capture insects. Reason (R): They grow in nitrogen-rich soil. MCQ with Answer and Explanation

Explanation:
Sewage contains organic matter that can be broken down by microorganisms, hence biodegradable. DDT, plastics, and mercury are non-biodegradable, persisting in the environment and accumulating in food chains (biomagnification). Biodegradable pollutants can be decomposed naturally, reducing long-term harm, but excessive loads can cause eutrophication. Non-biodegradable pollutants require special disposal and cause lasting ecological damage.

Explanation:
Genetic drift is a random change in allele frequency, more pronounced in small populations, and can reduce genetic diversity. Natural selection leads to adaptation.

Explanation:
Simple (endemic) goiter is caused by iodine deficiency, leading to low production of thyroid hormones. The pituitary secretes excess TSH, stimulating the thyroid to enlarge in an attempt to produce more hormones. Cretinism is congenital hypothyroidism, Graves' disease is autoimmune hyperthyroidism, Hashimoto's is autoimmune hypothyroidism. Iodized salt prevents goiter.